1、157安捷伦函数信号发生器 Agilent 33120A 的性能与使用说明安捷伦函数信号发生器 33120A 是数字式函数信号发生器。其内部永久存储着正弦波、方波、三角波、噪声、锯齿波、sin(x)/x 、负锯齿波、指数上升波、指数下降波、心电波，共 10 种函数信号。其中，正弦波、方波的频率范围为 100Hz15MHz，幅值范围为100mVP-P10V P-P。函数信号发生器有一个 HP-IB（IEEE-488）接口和一个 RS-232 接口，计算机通过接口可遥控函数信号发生器，在计算机中使用 HP BASIC 语言程序或 C 语言程序，能产生 12bit 40Msa/s 的任意波形，通过接
2、口写入函数信号发生器，函数信号发生器有四个可存储 16000 点的任意波形存储器。其具体的性能指标和基本操作方法见本节后摘录自“Agilent 33120A Function Generator User Guide”的内容。要知道详细的内容应阅读该仪器的“用户手册” 。 信号源显示电压与实际输出电压理想信号源的内阻应为零。若实际信号源的内阻为零，则信号源输出端一旦短路或负载电阻过小，信号源就会因功率过载而损坏。实际信号源一般都在其输出端串接一个电阻 Rs，使信号源既使短路，在短时间内也不会因功率过载而损坏，由此使信号源的保护电路有时间实现对信号源输出电路进行保护，同时发出过载警告。称信号源输
3、出端串接电阻 Rs 为信号源内阻。安捷伦 33120A（以下简称为信号源）的内阻为 50。由于有了信号源内阻 Rs，如图 1，信号源输出端的电压，即负载电阻 RL 上的电压，是信号源的电源 Es 在信号源内阻 Rs 和负载电阻 RL 上的分压，即VoE s。信号源内设置了两个负载电阻值，开机时默认为 RLD=50,通过操作可修改为RLD。在信号源开机默认为 RLD=50 时，信号源内部的电压源输出的电压为 Es，信号源显示屏上显示的电压是（1）ssLDsDisplayE21若实际负载不是 50，那么负载上实际得到的电压 Vo 为（2 ）ssLsoRV即信号源显示屏上显示的电压与负载上得到的实际
4、电压不一样，V oV Display。在实际使用时，当信号源的负载电阻，即电路的输入电阻 RL 与 50 可比时，信号源宜取 RLD=50 状态，这时 VoV Display ，但是 VDisplay 比较接近 Vo。信号源的负载电阻，即电路的输入电阻 RL50 时，信号源宜取 RLD状态，这时 VoV Display ，但是 VDisplay 比较接近 Vo。V o 究竟为多少应使用电压表具体测量。 关于本信号源的具体性能指标和基本操作使用方法以下关于本信号源的具体性能指标和基本操作使用方法摘自“Agilent 33120A Function Generator User Guide”。直接
5、阅读原版用户手册，比阅读翻译后的用户手册更有利于了解关于本信号源的具体性能指标和基本操作使用方法。在使用本信号源前，使用者图 1 信号源输出电压示意图158必须阅读以下的内容。附录Agilent 33120A Function Generator User GuideSpecificationsWAVEFORMSStandard Waveforms:Sine, Square, Triangle, Ramp, Noise, DC volts, Sine(x)/x, Negative Ramp, Exponential Rise, Exponential Fall, CardiacWaveform
6、 Length: 8 to 16,000 pointsAmplitude Resolution: 12 bits (including sign)Sample Rate: 40 MSa / secArbitrary Waveforms:Non-Volatile Memory: Four 16,000-point waveformsFREQUENCY CHARACTERISTICSSine: 100 Hz 15 MHzSquare: 100 Hz 15 MHzTriangle: 100 Hz 100 kHzRamp: 100 Hz 100 kHzNoise (Gaussian): 10 MHz
7、bandwidth8 to 8,192 points: 100Hz 5 MHz8,193 to 12,287 points: 100Hz 2.5 MHzArbitrary Waveforms:12,288 to 16,000 points: 100Hz 200 kHzResolution: 10 Hz or 10 digitsAccuracy: 10 ppm in 90 days, 20 ppm in 1 year, 18 28Temperature Coefficient:1 MHz): -65 dBc + 6 dB/octavePhase Noise: -55 dBc in a 30 kH
8、z bandSIGNAL CHARACTERISTICSRise/Fall Time: 20 nsOvershoot: 4%SquarewaveAsymmetry: 1% + 5 ns159Duty Cycle: 20% to 80% (to 5 MHz)40% to 60% (to 15 MHz)Rise/Fall Time: 40 ns (typical)Linearity: 0.1% of peak outputSettling Time: 250 ns to 0.5% of final valueTriangle, Ramp, ArbJitter: 25 nsOUTPUT CHARAC
9、TERISTICS150 mVpp 10 VppAccuracy (at 1 kHz): 1% of specified outputFlatness(sine wave relative to 1 kHz) 100 kHz: 1% (0.1 dB)100 kHz to 1 MHz: 1.5% (0.15 dB)1 MHz to 15 MHz: 2% (0.2 dB) Ampl 3VrmsAmplitude (into 50):21 MHz to 15 MHz: 3.5% (0.3 dB) Ampl 3Vrms5 Vpk ac + dcOffset(into 50): 3Accuracy4 2
10、% of setting + 2 mVOutput Impedance: 50 fixedResolution: 3 digits, Amplitude and OffsetOutput Units: Vpp, Vrms, dBmIsolation: 42 Vpk maximum to earthProtection: Short-circuit protected 15 Vpk overdrive 1 minuteMODULATION CHARACTERISTICS Carrier -3 dB Freq: 10 MHz (typical)Modulation: Any internal wa
11、veform plus ArbFrequency: 10 mHz to 20 kHz (0.05% to 2.5 kHz, then decreases linearly to 0.4% at upper limit)Depth: 0% to 120%AM ModulationSource: Internal / ExternalModulation: Any internal waveform plus ArbFrequency: 10 mHz to 10 kHz (0.05% to 600 Hz, then decreases linearly to 0.8% at upper limit
12、)Peak Deviation: 10 mHz to 15 MHzFM ModulationSource: Internal OnlyCarrier Frequency: 5 MHz max.Count: 1 to 50,000 cycles, or InfiniteStart Phase: -360 to +360Internal Rate: 10 mHz to 50 kHz 1%Gate Source: Internal or External Gate 5Burst ModulationTrigger Source: Single, External, or Internal RateF
13、requency Range: 10 mHz to 15 MHz (0.05% to 600 Hz, then decreases linearly to 4% at upper limit)FSK ModulationInternal Rate: 10 mHz to 50 kHz160Source: Internal / External (1 MHz max.)FREQUENCY SWEEPType: Linear or LogarithmicDirection: Up or DownStart F / Stop F: 10 mHz to 15 MHzTime: 1 ms to 500 s
14、ec 0.1%Source: Single, External, or InternalREAR-PANEL INPUTSExternal AM Modulation:5 Vpk = 100% Modulation 5 k Input ResistanceTTL (low true)Latency: 1.3 sExternal Trigger/ FSK Burst Gate: 5Jitter: 25 nsSYSTEM CHARACTERISTICSFunction Change: 7 80 msFrequency Change: 7 30 msAmplitude Change: 30 msOf
15、fset Change: 10 msSelect User Arb: 100 msConfiguration Times 6Modulation Parameter Change: 350 msArb Length Binary ASCII Integer ASCII Real 816,000 points 8 sec 81 sec 100 sec8,192 points 4 sec 42 sec 51 sec4,096 points 2.5 sec 21 sec 26 secArb Download Times over GPIB:2,048 points 1.5 sec 11 sec 13
16、 secArb Length Binary ASCII Integer ASCII Real 1016,000 points 35 sec 101 sec 134 sec8,192 points 18 sec 52 sec 69 sec4,096 points 10 sec 27 sec 35 secArb Download Times over RS-232 at 9600 Baud: 92,048 points 6 sec 14 sec 18 sec1 Add 1/10th of output amplitude and offset specification per for opera
17、tion outside of 18 to 28 range (1-year specification).2 100 mVpp 20 Vpp amplitude into open-circuit load.3 Offset 2 X peak-to-peak amplitude.4 For square wave outputs, add 2% of output amplitude additional error.5 Trigger source ignored when External Gate is selected.6 Time to change parameter and o
18、utput the new signal.7 Modulation or sweep off.8 Times for 5-digit and 12-digit numbers.9 For 4800 baud, multiply the download times by two; For 2400 baud, multiply the download times by four, etc.10 Time for 5-digit numbers. For 12-digit numbers, multiply the 5-digit numbers by two.161Operating Bas
19、icsThe Front Panel Function/Modulation keys Menu operation keys Waveform modify keys Single/Internal Trigger key(Burst and Sweep only) Recall/Store instrument state key Enter Number key Shift/Local key Enter Number “Units” keyQuick StartOne of the first things you will want to do with your function
20、generator is to become acquainted with its front panel. We have written the exercises in this chapter to prepare the function generator for use and help you get familiar with some of the front-panel operations.The front panel has two rows of keys to select various functions and operations. Most keys
21、 have a shifted function printed in blue above the key. To perform a shifted function, press (the Shift annunciator will turn on). Then, press the key that has Shiftthe desired label above it. For example, to select the AM (amplitude modulation) function, 162press (the shifted version of the key).Sh
22、ift AMIf you accidentally press , just press it again to turn off the Shift annunciator.ShiftMost keys also have a number printed in green next to the key. To enable the number mode, press (the Num annunciator will turn on). Then, press Enter Numberthe keys that have the desired numbers printed next
23、 to them. For example, to select the number “10”, press (next to the and keys).Enter Number 1 0 RecallIf you accidentally press , just press to turn off the Enter Number Shift CancelNum annunciator.To set the output frequencyAt power-on, the function generator outputs a sine wave at 1 kHz with ampli
24、tude of 100 mV peak-to-peak (into a 50 termination). The following steps show you how to change the frequency to 1.2 MHz.1 Enable the frequency modify mode. Press FreqThe displayed frequency is either the power-on value or the previous frequency selected. When you change functions, the same frequenc
25、y is used if the present value is valid for the new function.1.000,000,0 KHz2 Enter the magnitude of the desired frequency. Press or use the knob and arrow keys to change the Enter Number 1 0number.Notice that the Num annunciator turns on and “ENTER NUM” flashes on the display, indicating that the n
26、umber mode is enabled.1.2To cancel the number mode, press .Shift Cancel3 Set the units to the desired value.Press (MHz/mVpp)ShiftThe units are selected using the arrow keys on the right side of the front panel. As soon as you select the units, the function generator outputs the waveform with the dis
27、played frequency. To turn off the flashing digit, move the cursor to the left of the display using the arrow keys.1.200,000,0 MHzTo set the output amplitudeAt power-on, the function generator outputs a sine wave with amplitude of 100 mV peak-to-peak (into a 50_ termination).The following steps show
28、you how to change the amplitude to 50 mVrms.1 Enable the amplitude modify mode.Press Ampl163The displayed amplitude is either the power-on value or the previous amplitude selected. When you change functions, the same amplitude is used if the present value is valid for the new function.100.0 mVPP2 En
29、ter the magnitude of the desired amplitude. Press or use the knob and arrow keys to change the Enter Number 5 0number.Notice that the Num annunciator turns on and “ENTER NUM” flashes on the display, indicating that the number mode is enabled.50To cancel the number mode, press .Shift Cancel3 Set the
30、units to the desired value.Press (kHz/mVrms)ShiftThe units are selected using the arrow keys on the right side of the front panel. As soon as you select the units, the function generator outputs the waveform with the displayed amplitude. To turn off the flashing digit, move the cursor to the left of
31、 the display using the arrow keys.50. 00 mVRMSTo set a dc offset voltageAt power-on, the function generator outputs a sine wave with a dc offset voltage of 0 volts (into a 50 termination). The following steps show you how to change the offset to 1.5 mVdc.1 Enable the offset modify mode.Press OffsetT
32、he displayed offset voltage is either the power-on value or the previous offset selected. When you change functions, the same offset is used if the present value is valid for the new function.+0.000 VDC2 Enter the magnitude of the desired offset. Press or use the knob and arrow keys to change Enter
33、Number 1 5the number.Notice that the Num annunciator turns on and “ENTER NUM” flashes on the display, indicating that the number mode is enabled. Notice that toggles the displayed value between + and .-1.5To cancel the number mode, press .Shift Cancel1643 Set the units to the desired value.Press (kH
34、z/mVrms)ShiftAt this point, the function generator outputs the waveform with the displayed offset. Notice that the Offset annunciator turns on, indicating that the waveform is being output with an offset. The annunciator will turn on when the offset is any value other than 0 volts. To turn off the f
35、lashing digit, move the cursor to the left of the display using the arrow keys.-01.50 mVDCTo set the duty cycleApplies only to square waves. At power-on, the duty cycle for square waves is 50%. You can adjust the duty cycle for a square waveform from 20% to 80%, in increments of 1% (for frequencies
36、above 5 MHz, the range is 40% to 60%). The following steps show you how to change the duty cycle to 45%.1 Select the square wave function.Press Notice that the annunciator turns on, indicating that the square wave function is enabled.2 Enable the duty cycle modify mode.Press Shift % DutyThe displaye
37、d duty cycle is either the power-on value or the previous value selected.50 % DUTYThis message appears on the display for approximately 10 seconds. Repeat this step as needed.3 Enter the desired duty cycle. Press or use the knob and arrow keys to change the Enter Number 4 5number.Notice that the Num
38、 annunciator turns on and “ENTER NUM” flashes on the display, indicating that the number mode is enabled.45To cancel the number mode, press .Shift Cancel4 Output the waveform with the displayed duty cycle.Press Enter45 % DUTYTo output a stored arbitrary waveformThere are five built-in arbitrary wave
39、forms stored in non-volatile memory for your use. You can output these waveforms directly from non-volatile memory. The following steps show you how to output an “exponential rise” waveform from memory.165Shift Arb List 1 Display the list of arbitrary waveforms.Press Shift Arb ListThe list contains
40、the five built-in arbitrary waveforms (sinc, negative ramp, exponential rise, exponential fall, and cardiac). The list may also contain up to four user-defined arbitrary waveform names. The first choice on this level is “SINC”.SINCThis message appears on the display for approximately 10 seconds. Rep
41、eat this step as needed.2 Move across to the EXP_RISE choice. Press EXP_RISE3 Select and output the displayed arbitrary waveform.Press EnterNotice that the Arb annunciator turns on, indicating that the output is an arbitrary waveform. The waveform is output using the present settings for frequency,
42、amplitude, and offset unless you change them.The selected waveform is now assigned to the Arb key. Whenever you press this Arbkey, the selected arbitrary waveform is output.To output a dc voltageIn addition to generating waveforms, you can also output a dc voltage in the range 5 Vdc (into a 50 termi
43、nation). The following steps show you how to output +155 mVdc.1 Press the key and hold it down for more than 2 seconds.OffsetTo enter the dc voltage mode, press the key or any key in the top row of Offsetfunction keys and hold it down for more than 2 seconds. The displayed voltage is either the powe
44、r-on value or the previous offset voltage selected.DCV+0.000 VDC2 Enter the magnitude of the desired voltage. Press or use the knob and arrow keys to change the Enter Number 1 5 5number.Notice that the Num annunciator turns on and “ENTER NUM” flashes on the display, indicating that the number mode i
45、s enabled.155To cancel the number mode, press .Shift Cancel3 Set the units to the desired value.Press (kHz/mVrms)ShiftAt this point, the function generator outputs the displayed dc voltage. Notice that the 166Offset annunciator turns on (all other annunciators are off), indicating that a dc voltage
46、is being output. The annunciator will turn on when the offset is any value other than 0 volts.+155.0 mVDCTo store the instrument stateYou can store up to three different instrument states in non-volatile memory. This enables you to recall the entire instrument configuration with just a few key press
47、es from the front panel. The following steps show you how to store and recall a state.1 Set up the function generator to the desired configuration.The state storage feature “remembers” the function, frequency, amplitude, dc offset, duty cycle, as well as any modulation parameters.2 Turn on the state
48、 storage mode.Press Shift StoreThree memory locations (numbered 1, 2, and 3) are available to store instrument configurations. The instrument configuration is stored in non-volatile memory and is remembered when power has been off.STORE 1This message appears on the display for approximately 10 secon
49、ds. Repeat this step as needed.3 Store the instrument state in memory location “2”. Press or use the knob and arrow keys to change the number.Use the up and down arrow keys to select the memory location.STORE 2To cancel the store operation, press again or let the display time-out Shift Storeafter 10 seconds.4 Save the instrument state.Press EnterThe instrument state is now stored. To recall the stored state, turn to the next page.To verify that th
